ALBERT

Description: The objective was to elucidate the effects of dietary supplementation with guanidinoacetic acid (GAA) on performance, egg quality and the liver antioxidant activity of laying hens. A total of 128, 72-week-old ISA Brown laying hens were randomly divided into four equal groups (32 birds), and each subgroup had eight replicates (four birds/cage). The control group (GAA0) fed the basal diet with no supplements, while the other experimental groups fed the basal diets supplemented with 0.5 (GAA1), 1.0 (GAA2) and 1.5 (GAA3) g of GAA/kg diet. The experiment lasted for 6 weeks. The addition of GAA at a rate of 1.5 g kg−1 significantly increased the hen-day egg production and egg mass as compared to the control group (P = 0.016 and 0.003, respectively). Although the egg weight was not affected (P = 0.521) by the dietary supplements, the shell ratio, shell thickness, yolk index and Haugh units increased linearly with the increase in the dietary supplements of the GAA (P = 0.036, 0.001, 0.012 and 0.004, respectively). The liver MDA levels decreased linearly with the increment in the dietary levels of the GAA (P = 0.012). Birds in the GAA2 and GAA3 showed a significantly higher liver nitric oxide level (52.50 and 54.21 mg/g, respectively) when compared with GAA0 and GAA1 groups (P = 0.029). Compared to the GAA0 group, all GAA-supplemented groups showed significantly higher liver ATP levels (P = 0.047). In conclusion, the dietary GA supplements at doses of 1.0 or 1.5 g kg−1 may improve the laying performance, antioxidant activity and the status of cellular energy metabolism in laying hens.

Description: Organic carbon (C) plays an essential role in the denitrification process as it supplies energy for N2O, N2 and CO2 producing reactions. The objectives of this study were to: (i) rank the reactivity of different C compounds found in manures based on their availability for denitrification and (ii) explore C-quality in different C sources based on their capacity to promote denitrification. Evaluation of different C-sources in promoting denitrification was conducted based on the molar ratio of CO2 production to NO3− reduction after incubation. Results of the first experiment (a 12-day investigation) showed that glucose and glucosamine were highly reactive C compounds with all applied NO3− being exhausted by day 3, and glucosamine had significantly high amount of NH4+-N present at end of the experiment. The glucose and glucosamine treatments resulted in significantly greater cumulative CO2 production, compared to the other treatments. In the second experiment (a 9-day investigation), all NO3− had been depleted by day 6 and 9 from acetic acid and glucose, respectively, and the greatest cumulative CO2 production was from acetic acid. The CO2 appearance to NO3− molar ratios revealed that glucose and glucosamine were compounds with highly available C in the first experiment. In the second experiment, the pig slurry and acetic acid were found to be C-sources that promoted potential denitrification. The application of slurry to soil results in the promotion of denitrification and this depends on the availability of the C compounds it contains. Understanding the relationship between C availability and denitrification potential is useful for developing denitrification mitigation strategies for organic soil amendments.

Description: SUMMARYThe purpose of the current work was to study phosphorus (P) metabolism in growing sheep supplemented with different levels of dicalcium phosphate using an extant mathematical model. Twelve male non-castrated Santa Inês sheep, weighing 23 (±2·2) kg, received a basal diet unsupplemented or supplemented with dicalcium phosphate to provide 1·5, 3·0, 4·5 g of P/animal per day (treatments T1 to T4, respectively). After 3 weeks adaptation, 7·4 MBq of32P was injected into the jugular vein of each animal. Samples of blood, faeces and urine were collected every day during a 7-day period and thereafter the animals were sacrificed and samples from liver, kidney, heart, muscle and bone were collected for specific activity and inorganic P determinations. The flows between gut and plasma were similar for each treatment except for T1, which showed the lowest values for both flows (P

Description: SUMMARYMedial claws from the right hind feet were obtained post mortem from four 19–20-month-old beef heifers and from four 28-month-old first-calving dairy heifers 3–4 days postpartum. X-ray diffraction (XRD) studies were undertaken on samples of soft and hard (cornified) integumental tissues of dorsal wall, sole and heel (bulb) for varying sites and planes of exposure. The measurements were interpreted as defining diffraction patterns and intermolecular spacings of cytoskeletal and extracellular fibrous structural proteins. The orientation of these proteins was examined in relation to physical characteristics and function including bearing of body weight by these tissues.Physical measurements taken included impression hardness which showed typically greater values for wall than sole and variable differences between horn of dairy and beef origin and husbandry systems. Claws from dairy heifers had significantly smaller values for toe (dorsal wall) angle, claw height and heel height and thickness of solear horn and heel soft tissue. Although few were studied, the results reflected typical husbandry origins and indicated the susceptibility to the lesion formation well recognized in postpartum dairy cattle.Typical XRD patterns for horn samples showed defined arcs of reflectance on the equatorial axis consistent with findings for the presence of α-helices in fibrils reported to occur in other hard-keratin-containing integumental tissues. However, reflectance on the meridional axis also reported for these other tissues was not detected. A similar defined pattern was obtained for less than 0·10 of samples of internal soft pre-cornified epidermal and attached dermal tissue although the values for intermolecular ‘d’ spacing for these were consistent with those reported for type I collagen. Diffuse reflection patterns were thus evident for the majority of samples of soft tissue epidermis and dermis and also for adipose tissue of the digital cushion.The formation of defined arcs of reflectance allowed the determination of fibril alignment in wall and solear horn. For the orientated samples of dorsal wall horn tissue, the outer layer showed a longitudinal angle of orientation essentially maintained proximal to distal. This pattern was maintained throughout the depth of horn at the proximal site. In contrast, layers in mid-wall and towards the distal edge showed a greater circumferential (horizontal) orientation in sections collected anterior to posterior towards the inner corial, including laminar, tissues. The orientation of fibrils in inner wall horn appears to relate to the direction of load-bearing forces in connecting horn to the distal phalanx. Horizontal alignment of fibrils was observed in the sole. In presenting the long axis of cells to the ground surface this orientation may facilitate erosive forces and contribute to the thinning of cornified sole horn under adverse underfoot conditions.

Description: SUMMARYThe development of the genetic control of nematode resistance in growing lambs is of biological interest, as well as being important in terms of designing practical strategies to breed for increased nematode resistance. The current paper demonstrates the use of random regression techniques for quantifying the development of the heritability of faecal egg count (Fec), the indicator of nematode resistance, in growing lambs and predicted inter-age genetic and phenotypic correlations for Fec. Fec data from 732 lambs, collected at 4-week intervals fromc. 8–24 weeks of age, were analysed using random regression techniques. Random effects fitted in the model included genetic, individual animal environmental, litter and residual random effects. Output (co)variance components were interpolated to weekly time points. Individual variance components showed complex patterns of change over time; however, the estimated heritability increased smoothly with age, from 0·10 to 0·38, and showed more stable time trends than were obtained from univariate analyses of Fec at individual time points. Inter-age correlations decreased as the time interval between measurements increased. Genetic correlations were always positive, with 0·6 of all possible inter-age correlations being greater than 0·80. Phenotypic correlations were lower, and decreased more quickly as the time interval between measurements increased. The results presented confirm biological understanding of the development of immunity to nematode infections in growing lambs. Additionally, they provide a tool to determine optimal sampling ages when assessing lambs' relative resistance to nematode infections.

Description: SUMMARYSince many soils used for growing potatoes in the UK are likely to be close to their plastic limit for cultivation during early spring, there exists the potential for soil compaction to occur during planting which will restrict root penetration. A series of experiments showed that soil compaction delayed emergence, reduced rate of leaf appearance and ground cover expansion, shortened canopy cover duration and restricted light interception, which combined to reduce tuber yield. Rooting density and maximum depth of rooting were reduced, particularly where compaction was shallow. In some soils, irrigation helped alleviate some of the effects of compaction but in others it exacerbated their severity. Using a cone penetrometer, relationships between rate of root penetration and soil resistance (Ω) were established from a number of experiments and replicated blocks in commercial fields and an overall relationship of the formy=16·3–4·08Ω mm/day was produced. Root penetration rates ofc. 20 mm/day were measured in the intensively-cultivated ridge zone but growth rates were halved at a Ω of 1·5 MPa. A survey of 602 commercial fields showed that two thirds of fields had Ωs ⩾3 MPa (where root growth rates would be

Description: Review Articles S. MANGALASSERY, S. SJÖGERSTEN, D. L. SPARKES, S. J. MOONEY, The Journal of Agricultural Science , Volume 153 Issue 07 , pp 1151-1173 Abstract

Description: Research Articles S. WANG, Z. LIANG, D. SUN, F. DONG, W. CHEN, H. WANG, R. JING, The Journal of Agricultural Science , Volume 153 Issue 07 , pp 1234-1245 Abstract

Description: Research Articles C. FERNÁNDEZ, M. C. LÓPEZ, M. LACHICA, The Journal of Agricultural Science , Volume 153 Issue 07 , pp 1302-1309 Abstract

Description: Research Articles B. WANG, H. LIU, X. H. WANG, J. M. LI, Y. B. MA, X. W. MA, The Journal of Agricultural Science , Volume 153 Issue 07 , pp 1247-1256 Abstract